U.S. President Joe Biden has summoned an Israeli delegation to Washington as he tries to dissuade Israel from launching an assault on southern Gaza's Rafah.

The offer, which came Monday during a phone call with Israeli Prime Minister Benjamin Netanyahu, is one of the clearest attempts yet by Biden to rein in the key US ally, amid fears that a full attack on Rafah could drastically worsen the already huge death toll and humanitarian crisis in Gaza.

The White House said separately that Israel had killed one of Hamas's top commanders in a strike in Gaza.

"I asked the Prime Minister to send a team to Washington to discuss ways to target Hamas without a major ground operation in Rafah," Biden said on X after speaking to Netanyahu for the first time in more than a month.

Biden also "reiterated the need for an immediate cease-fire as part of a deal to free hostages, lasting several weeks, so we can get hostages home and surge aid to civilians in Gaza."

Roughly 1.5 million people are sheltering in Rafah, most of them displaced by Israel's relentless assault on other parts of Gaza since the Oct. 7 Hamas incursion triggered the latest conflict.

The White House earlier said Biden had warned Netanyahu that an offensive on Rafah would be a "mistake," in their first call since Feb. 15.

"A major ground operation there would be a mistake," National Security Advisor Jake Sullivan told reporters.

"It would lead to more innocent civilian deaths, worsen the already dire humanitarian crisis, deepen the anarchy in Gaza, and further isolate Israel internationally."

Netanyahu agreed to send a team of senior Israeli officials to Washington in the coming days to discuss "alternative approaches that would target key elements of Hamas," he added.

Sullivan separately confirmed that Israel had killed Hamas's third-in-command, Marwan Issa, in an operation last week. Israel previously said he had been targeted in a Gaza airstrike but did not confirm his death.

'Threat to Israel'

Biden has offered Israel unequivocal support since Oct. 7, sending billions of dollars in military aid, but has become increasingly frustrated by Netanyahu's failure to curb civilian deaths or let in vital aid.

The U.S. president also faces growing political pressure at home, with opposition among Arab-Americans and young voters posing a risk to his reelection chances in November.

Netanyahu said in a statement after the Biden call that he had reiterated "Israel's commitment to achieving all of the war's objectives."

He cited the objectives as eliminating Hamas, winning the release of all hostages held by the group and "ensuring that Gaza will never present a threat to Israel."

He also pointed to the provision of "essential humanitarian aid that helps achieve these aims."

Biden was caught on a hot mic just over a week ago saying he would have a "come-to-Jesus meeting" with Netanyahu.

He also praised a "good speech" last week by Democratic Senate Majority Leader Chuck Schumer calling for new elections in Israel.

Since Oct. 7, Israel has killed nearly 32,000 people in Gaza, most of them women and children, according to the local Health Ministry.